import java.util.Arrays;
import java.util.Scanner;

public class demo2 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int m=scanner.nextInt();
        int n=scanner.nextInt();
        m++;
        n++;
        int[][] arr = new int[m][n];
        Arrays.fill(arr[0],1);;
        for(int i=0;i<m;i++) {
            arr[i][0]=1;
        }
        for(int i=1;i<m;i++) {
            for(int j=1;j<n;j++) {
                arr[i][j]=arr[i-1][j]+arr[i][j-1];
            }
        }
        System.out.println(arr[m-1][n-1]);
    }
}
